The invention relates to a control device for manually inputting information into a device, having a final control element whose position can be changed under the effect of an activation force and which is connected to a converter for generating electrical signals which characterize the position of the final control element, and having a motor element which is connected to the final control element and which exerts, under the control of the electrical signals, a force on the final control element, the size and direction of the force being dependent on the position of the final control element and/or on the information which is to be input. From the prior art, it is known to connect the final control element to a converter in the form of an incremental position encoder via a shaft and to a motor via a further shaft.
It is a further disadvantage here that because of the additional incremental position encoder, this design requires a large amount of space. For this reason, the object of the invention is to specify a corresponding control device with a haptic feedback which requires only a small amount of space.
This object is achieved by virtue of the fact that the converter is composed of a rotor of the motor element and sensors which respectively emit an electrical signal as a function of the position of the rotor. The rotor of the motor element therefore also fulfills the additional function of an angular position encoder of the converter. The invention thus provides the advantage that only the additional sensors are necessary for the converter. A rotor which is designed as a diametrically magnetized disk provides a simple and economical solution for the rotor. In conjunction with at least two Hall sensors, it is possible to determine the precise rotary angle within the range of 360xc2x0 from the voltages which the magnetic field of the diametrically magnetized disk brings about in the Hall sensors. Two Hall sensors are completely sufficient for this.
If the two Hall sensors are arranged offset by 90xc2x0 with the same radial interval in the direction of rotation, the position of the rotor can be calculated particularly easily.
By using a pair of cross coils it is possible to make the motor element of a very compact design. Furthermore, any desired torque characteristic at any desired angle can be achieved by respectively actuating the two coils in different ways. The torque characteristic and the angle can thereby be correspondingly adjusted as desired by changing the actuation. The desired moment characteristic curves are stored in a memory and can be read out of it. Thus, different torques can be generated depending on which data are read in. Thus, for example when the volume is adjusted by means of a corresponding moment profile, catch positions can be simulated while during the adjustment of the volume of individual loudspeakers of a device (balance, fader), a speed-proportional friction is simulated which gives the person using the control device a sensation of adjusting a potentiometer.
By using a coil former onto which the coils are wound, the motor element with the coils can be manufactured in a simple and robust way. The motor is prevented from becoming dirty by virtue of the fact that the coil former completely encloses the rotor.
The torque acting on the final control element can be increased by using a gear mechanism between the motor element and the final control element. The embodiment of the final control element as an adjusting knob can be manually controlled satisfactorily.
The sensors are particularly easy to mount if they are arranged on a printed circuit board which is mounted underneath the coil and/or the coil former.
By enclosing the underside and largely also the sides of the control device with a magnetic return pot, additional protection against contamination is obtained. The use of magnetically soft material with a high hysteresis provides, on the one hand, shielding of interference in the form of electromagnetic fields which are produced within the control device and which would otherwise penetrate to the outside as well as in the form of fields which would otherwise act on the control device from the outside. A high level of hysteresis also simplifies control by virtue of a high attenuation of the magnetic circuit. Furthermore, a material such as St 37, for example, is particularly inexpensive. In addition, a magnetic return pot made of magnetically soft material raises the working point of the magnet and thus increases its efficiency.